Do these genes make me look fat?

Feel guilty because you're stout? Or smug because you're thin? You may both be wrong.

By Steve Weinberg, Special to the Times
Published May 18, 2007

In her book Re-thinking Thin, New York Times science journalist Gina Kolata reaches conclusions quite likely to make enemies of every diet marketer alive. The diet marketers will probably find allies among the millions of thin Americans who find overweight Americans disgusting.

Kolata's first conclusion is straightforward: Diets almost never lead to better health for those who try them. Not the Atkins diet or the South Beach diet or Weight Watchers or Jenny Craig. In fact, most diets fail to permanently reduce the poundage of most users.

The second conclusion is less straightforward, because the human body is an extremely complicated mechanism. But here it is: Overweight women and men are rarely that way because they lack willpower near the refrigerator and in restaurants. Instead, they are overweight primarily because of the genes they inherited. Phrased differently, so that condemnatory thin people can understand, thin women and men are rarely that way because they possess willpower near the refrigerator and in restaurants. Instead, they are thin primarily because of the genes they inherited.

The research is overwhelming, Kolata says: Fat people find it difficult to lose lots of weight permanently, just as thin people find it difficult to gain lots of weight permanently. In a way, weight is like height. A girl baby with her parents' genes who is well fed as an infant might end up 5 feet 6 inches tall rather than the 5 feet 4 inches of her mother. But it would be extremely unusual for that girl baby to end up 6 feet tall. Even if she wants to end up at 6 feet, there is nothing practical she can do to reach even 5 feet 7.

Whether readers are prone to like or dislike the book's conclusions, they should find it easy to digest, because Kolata is a first-rate author. She constructs the narrative along two alternating tracks. One track, consisting of eight chapters, covers the research of scientists across the United States and, to some extent, across the globe. Some of those scientists are studying fat cells, some are studying brain cells. Some are mounting statistically significant, long-term research studies comparing, for example, individuals on the low-carbohydrate Atkins diet against individuals on a less gimmicky count-your-calories-every-meal diet.

The second track in the narrative, consisting of seven interludes, follows the individuals who agree to participate in a carefully controlled weight loss study at the University of Pennsylvania. The researchers randomly place half of the volunteers on the Atkins diet, the other half on the count-your-calories diet.

It is those individuals whose sagas are most likely to remain seared in readers' brains at the end of Kolata's book, individuals like Carmen J. Pirollo, a Philadelphia area schoolteacher. At the beginning of the two-year study, he stands 5 feet 11 inches and weighs 265 pounds. During the two years, he loses significant weight.

Because feelings about diets and obesity are inextricably linked to the body image of the individual doing the thinking, it is significant to know that Kolata is thin and always has been. She is not interpreting the scientific evidence to rationalize obesity.

It is nearly as significant to know physical data about the reviewer. At age 30, I had reached 6 feet in height and weighed about 150 pounds. Thin. Now, almost 60, I am the same height, but weigh about 250 pounds. Overweight. Obese, even, by many measures.

Yet I play tennis and baseball regularly, ride my bicycle or walk everywhere I go, climb up and down steps without getting winded, score well in my checkups at the medical clinic, function fine on five hours of sleep and generally feel healthy.

I dislike the way I look, to be sure, so Kolata's book is balm to me.

By the way, you might be wondering, does Pirollo regain the weight he lost while being observed by specialists and by Kolata? Readers who care about the obesity debate being carried on every day across the United States will want to read Kolata's book to find out.

Steve Weinberg is a biographer and journalism professor in Columbia, Mo.

Rethinking Thin: The New Science of Weight Loss - and the Myths and Realities of Dieting